The ultimate goal of this research is to improve the biocompatibility and performance of implantable microelectrodes for neurological sensing and stimulation. Neural prostheses have traditionally been fabricated from metals. The effectiveness of metallic implant devices can be compromised by exposure to the corrosive physiological environment. Elemental silicon is finding increasing application in implants due to its electrical properties, flexibility, and micromechanical processability. The interfacial interaction between metallic microelectrode arrays and target neural cells, however, needs to be improved for successful chronic neuroprosthetic treatments. The proposed research objective is to develop a novel composite coating for silicon microelectrodes that offers tailorable surface properties, with excellent biocompatibility, physiological stability and electrical conductivity. Conducting polymers will be synthesized within a porous bioceramic coating matrix to yield ordered structures for maximizing conductivity while preserving the desired physical properties. The conductive ceramic coatings will be applied to silicon-based electrodes and tested for electrical properties, adhesion, and durability in a simulated physiological environment. The electrical property evaluations will be conducted with standard implant device geometries to establish the feasibility of the proposed bioceramic-coated silicon electrodes. Phase II objectives would include optimization of coatings for processability, electrical properties, and physiological compatibility, and chronic implantation testing. [unreadable] [unreadable] [unreadable]